Effect
on SACC list:If
this proposal passes, Milvago chimango
would become Phalcoboenus chimango

Background: Milvago
chimango traditionally has been treated in Milvago, and I am unaware of any doubts concerning its placement
there.In fact, Brown & Amadon
(1968) treated them as forming a superspecies, but this is clearly an error
because they overlap fairly extensively in their distribution (in Paraguay,
Uruguay, extreme S Brazil).Vuilleumier (1970) questioned their close relationship because of
differences in shape and ecology, but he retained chimango in Milvago.

New
information:Fuchs et al. (2012) sampled all of the
caracaras using DNA sequence data from mtDNA (2308 bp) an nDNA (5008 bp).Milvago
chimango was not the sister taxon to M.
chimachima in either the mtDNA or nDNA analyses, but was the sister to Phalcoboenus with weak or no
support.However, in the
concatenated dataset, support for that relationship was much stronger.In all analyses, Daptrius ater was sister to M.
chimachima.Clearly, Milvago as traditionally defined is not
monophyletic.Here is their species
tree:

Fuchs et al. (2012) considered 4 taxonomic options:

1. One genus: Merge all species from Milvago and Phalcoboenus
into Daptrius (which has priority).

2. Two genera: Move Milvagochimachima into Daptrius and Milvagochimango into Phalcoboenus.

3. Three genera: Move chimango
into Phalcoboenus.

4. Four genera: Retain traditional generic boundaries and
describe a new genus for chimango.

Recommendation:I have no
recommendation on this one, and have written the proposal to follow the
recommendation of Fuchs et al.Their option 4 is clearly out in the absence of a genus for chimango, but otherwise I have no
opinion on the other three.Although I once knew D. ater
and M. chimachima very well, I don’t
know the rest well enough to contribute to the subjective evaluation, and will
listen to what others have to say.Strictly on plumage and general shape, Daptrius and Phalcoboenus
are fairly similar, and Daptrius ater
is certainly more similar to them in general behavior and ecology than it is to
its former congener (now Ibycter
americanus) and obviously more similar in plumage to Phalcoboenus than it is to Milvago
chimachima (thus I would rank Option 2 fairly unpalatable).So, pending input from more
knowledgeable people, I think Option 1 (Milvago
and Phalcoboenus into Daptrius) is viable – these are all
generalists of open country with roughly similar size, proportions, and
behavior.

A YES vote
would endorse the solution proposed by Fuchs et al. (2012), Option 3 above, and
a NO would indicate favoring another option (presumably #1?).

Literature
Cited

BROWN, L. AND D. AMADON.
1968.Eagles, hawks,
and falcons of the world. 2 Vols. Country Life Books, Hamlyn, Middlesex, U.K.

Comments
from Zimmer:
“NO.Like Van, I don’t feel that I
know the species in Phalcoboenus well
enough to properly inform my opinion on this one.However, I do know the other species (Daptrius ater, Milvago chimachima & M.
chimango) well, so here goes…Based on the molecular data, we clearly need
to do something with chimango.Looking at morphology (particularly
plumage patterns), vocalizations, and ecology, it doesn’t make much sense to me
to shift chimango to Phalcoboenus, while retaining Daptrius (most similar in plumage to Phalcoboenus, but sister to chimachima) and Milvago (for chimachima).Therefore, I would say NO to the
proposed Option #3, and YES for Option #1 (merging all species from Milvago and Phalcoboenus into Daptrius,
which has priority), which would still be consistent with the molecular data.

Comments
solicited from Nacho Areta: “This is a tough one to decide upon.I lean toward the single genus
treatment: as you said, they are all fairly open-area generalists and they all
share their slim wings (with a noticeable 'primary break') and long, slender
tails, giving them a very similar shape. Biogeographically, the only coherent
group appears to be Phalcoboenus sensu
stricto, whose species seem to be less vocal than Ibycter, Daptrius, or the
Milvagos and are restricted to cold
Andean-Patagonian open habitats. I don't think that any of the 'intermediate'
options is reasonable, and I think that either a five genera or a single genus
option are the most palatable choices here. The oddballs are the Milvagos (if they were not here, I
suspect everybody would be happy to have a single genus for the black-and-white
and painted-face members). Merging chimango
into Phalcoboenus without merging
chimachima into Daptrius seems like the worst possible option, as there are more
(or as many) differences in plumage and vocalizations between chimango-Phalcoboenus than between chimachima-Daptrius. If separate genera
are kept for chimango and chimachima, then the same should be done
for Ibycter, Daptrius, and Phalcoboenus.
If pushed hard, I would argue that merging them in a single genus would be more
informative than over-splitting this small group of birds into five different
genera. Looking at Falco, the merger
becomes easier to digest. Yet perhaps the best thing to do is to wait for a
more solid phylogeny with well-supported branches?

Comments
from Pearman:“I agree that Phalcoboenus
is the most coherent group and this is a crucial point in relation to the
taxonomy. The four Phalcoboenus are robust, have three distinct age-related
plumages (the juveniles strongly resemble one another including australis),
adults always exhibit a white terminal band to (contra Nacho) a fairly
broad tail (unlike chimachima/chimango), which is often fanned
somewhat in flight, have a wing shape that is closest to Caracara but
with round-tipped primaries (unlike other caracaras), and their raucous grating
calls are very different from all the other genera/species mentioned, and they
are also less vocal in general terms. None of these features tally with chimango,
or chimachima or Daptrius making options 2 and 3 untenable.Daptrius and narrow-tailed Milvago
chimachima and chimango all produce different kinds of screaming
vocalizations.It is also
noteworthy that chimachima is the only species showing three very
distinct age-related plumages, unlike chimango and Daptrius. My
personal view is that we have three species which just don’t sit well with Phalcoboenus
and that there is too much information that would be forfeited with a rather radical
merger of all genera into Daptrius (option 1) which, by itself, is an
oddball caracara. Therefore, I believe that the erection of a new genus for chimango
(option 4) is a better solution.

I’m
not saying that I am going to write up a new genus, but I think this is a
better course of action than lumping into Daptrius, which is kind of an
easy way to sweep this problem under the carpet.”

Comments from Nores: “NO.First, I do not understand why all the
species are considered open-area generalists, when Daptrius and Ibycter are,
at least in Amazonia, forest birds? I have watched the two species on many
occasions and always in forests. Second, Milvago
chimango and M. chimachima have
very similarbehavior andthe young of M.
chimachima are virtually the
same as adultsof M. chimango. I have seen more than one experiencedornithologistsconfusethe young ofM.
chimachima with M. chimango. When Ifirst sawM. chimachimayounginBrazil more than 30years ago, I thought how odd thatM. chimangoreaches so far north. Anyway,ifweconsidermainlythemolecularanalysis, then we can almostforget aboutthe morphological. Fuchs’tree, in this
respect, is one of themostillogicalI've
ever seen. I remember a sentence by Robbins: ‘I was particularly
surprised with the molecular data and I quickly realized that morphology and
vocalizations (except for mostly sister relationships) often lead to wrong conclusions
about relationships’.
I vote option 1.

Comments
from Robbins: “NO.Once
again, a subjective decision on how to deal with a monophyletic clade.Why not put all in one genus, Daptrius.”

Comments
from Stotz:
“NO.I favor option 1, all in Daptrius.”

Comments from Sergio H.
Seipke: ”I was prompted by Nacho
Areta to submit for your consideration my views on this subject. As I
read previous comments made by others here, I found some inconsistencies with
my own observations. Most of what follows is the result of my own work in
the field and in museums, it has not been published elsewhere, and it will be
included in a book I am preparing (Seipke, S. H. Raptors of South America. Princeton University Press.) I
wandered beyond the point in question here (Transfer Milvagochimango
into Daptrius) as I deemed it necessary. I used specific
epithets standing alone to refer to individual species (instead of using
customary generic names) as to avoid confusion or ambivalences.
Eventually, I chose not to be too formal at times, as it is more fun.

“Americanus is truly way out there on its own in most respects
among the Neotropical caracaras. Adults and juveniles look virtually the
same. They are extremely vocal (and loud!). They are, for the most
part, food specialists (wasps, bees, hornets) and show very specialized feeding
behavior (they fly by insects nests hitting them until they fall and feed only
when adult occupants have left). They have red feet. Their tails are
obviously graduated. Their flight profile (and behavior) is more akin to
guans or chachalacas than to any caracara. They are true forest birds, as
they occur in primary forests even far away from bodies of water or edges
(although they would wander to edges where deforestation advances rapidly or
small openings in continuous forest). Placing americanus into
anything other than its own genus will mask this significant differentiation.

“Carunculatus, megalopterus, albogularis and australis
share several plumage traits (developmental sequence) not present in the rest
of the species in the clade considered (Polyborinae sensu Fuchs et
al. 2012, a rather unfortunate name if I may say so, as Polyborus is
a synonym of Circus!). Namely, they all have four immature basic
plumages plus a definitive basic plumage. The first two immature basic
plumages are very similar (overall brown), and the reason why they have only
been described so far only for australis. The progression of
character states from basic I to basic IV is very similar for all four species
(to the point that all three truly continental forms can be readily told apart
only after well into the third year of age). In all four species, these
two 'cryptic' juvenile plumages can be told apart by the shape of the primaries
(pointed in the first basic, rounded in the second basic), the coloration of
the bill, facial skin, and legs, and other minor differences. All four
species are broad-tailed. These species can and do soar on thermals
without flapping (unheard of in other caracaras, except rarely in chimango).
All four species are ground dwellers and take carrion, insects, and other
animals they can catch on foot.

“Chimango also has only two age plumages (juvenile and adult), and both
are quite similar. But unlike any other caracara (that I am aware of) chimango
shows sexual dimorphism in the coloration of bare parts of adults of different
sexes.

“Although ater, chimachima, and chimango
(the 'screaming-caracaras') share overall proportions (all three being rather
slim and narrow-tailed), the first two are longer-tailed, shorter-winged birds
(very obvious on perched individuals) that fly on rather stable, linear
trajectories, even when flapping, whereas chimango, on the other hand,
is very erratic on the wing, even when gliding.

“Both chimango and chimachima are rather catholic in
their habitat use, the former having populations very partial to (temperate)
forests, the later occurring in open grasslands and primary forest along major
rivers too (e. g., sand banks). On the other hand, ater is rather
partial to major rivers in primary forest (where it is syntopic with chimachima).
Bottom line being, habitat is of limited use here.

“In view of all-of-the above I think that the most informative
treatment of the 'Polyborinae', one that would not necessarily conflict
with Fuchs et al. 2012, would be to place ater and chimachima
together in Daptrius and leave everything else the same.

“Placing chimango
into Phalcoboenus would—well—destroy our notion of what a Phalcoboenus
is. Merging all into Daptrius is, from my perspective, quite unnecessary,
and artificially homogenizing. If you can have Ibycter americanus
standing alone, then you should be able to live with a Milvago chimango
too. If you must place chimango into Phalcoboenus, please
don't label everything Daptrius. Thanks!"

Comments
from Pacheco: “NO. I consider the comments of Sergio perfectly pertinent. For all
these reasons, I defend also that Chimango Caracara deserves a monotypic genus.
Something like "Protodaptrius" to be published by someone.”

Comments
from Stiles:
“NO.Here, I tend to agree with
Sergio: lumping everything into Daptrius produces
a virtually undiagnosable soup, and I tend to dislike the “toss the whole mess
into the same bag” approach, as it also implies sweeping a lot of useful
biological information under the rug.As I am not very familiar with either Phalcoboenus or chimango
(especially their plumage sequences) and given the weak support for lumping the
latter into the former, I’d rather see a new genus for chimango if the differences are as great as appears.Ibycter
is clearly OK as a monotypic
genus.The only real surprise to me
is the relatively close relationship indicated between Daptrius ater and Milvago
chimachima.To me, they are
very different birds in habitat, sociality, plumage sequences and foraging:
about the only similarities are that they both “scream”, and a rather general
resemblance in shape.Like Manuel,
I certainly donęt consider D. ater an
“open country” bird.Hence, I tend
to favor option 4, though it would be nice to have better genetic data to
assure the placement of chimango.”

Comments from Pérez-Emán: “NO. I am familiar with both Daptrius ater and Milvago
chimachima but not much with Phalcoboenus
and M. chimango, so comments from
Sergio, Pearman and Nacho are particularly useful to evaluate this proposal.
Fuchs et al. (2012) phylogenetic hypothesis does not really support merging chimango into Phalcoboenus, so I would discard both options 2 and 3.
Additionally, as Gary mentioned, ater
and chimachima seem to me very
different birds. I would favor option 4 as it will preserve basic differences
among this group of birds, but it is contingent upon the availability of a
name. Option 1, the other alternative, would group a somehow similar species of
birds including some variability unique to each current genus. Differences
between option 1 and 4 depends on how much variability we would want to include
into a genus.”